Various roll-up truck covers are available to meet statutory requirements in the majority of the states. One type in wide use employs a stationary take-up roll mounted on a headboard adjacent a front wall of a truck body and from which the flexible cover is drawn rearwardly to a body covering position by a pair of swinging arms on opposite sides of the body. As the cover is drawn from the take-up roll, the diameter of the roll is of course reduced and when the truck is in motion air flows beneath the reduced diameter roll causing the cover to billow and to flap violently. Such covers are also characterized by poor sealing adjacent side walls of the truck body and particularly at the junction of the side walls and the headboard. The resultant billowing and violent flapping not only causes the loss of fine particulate material in transit but also severely reduces cover life, sharp and jagged particulate material in the truck body being impinged by the flapping cover and often marring and tearing the cover during opening and closing operations with the cover being drawn or dragged thereover.
An improved type of roll-up cover, disclosed more fully in my U.S. Pat. No. 4,050,734 entitled Roll-Up Truck Cover Assembly, granted on Sept. 27, 1977, has the take-up roll mounted on the swinging arms with a free end portion of the cover secured across a front end portion of the body. When the free end portion of the cover is secured at the front end of the body, it is possible to effect a careful attachment of the cover and to cover the areas at the junctions of side and end walls with short skirts or wings on the cover so as to prevent the entry of air beneath the cover when the truck is in motion. This results in a significant improvement in the billowing or flapping difficulty and particulate leakage and cover damage is also avoided, the dragging effect of the cover over sharp or jagged objects also being avoided with the take-up roll on the arms. There is, however, one remaining problem with regard to billowing and flapping of the cover in transit. With either of the aforesaid arrangements, there may be a tendency for the cover to inadvertently pull from the take-up roll resulting in a slack condition of the closed cover and in billowing and flapping. This inadvertent or unintended roll-out or draw-out of the cover from its take-up roll has remained an unsolved problem with both types of roll-up truck covers.
It is the general object of the present invention to provide a flexible roll-up truck cover assembly which exhibits a high degree of ease and convenience in use, which provided for tight closure of all areas of the truck body opening when in the closed position, and which is maintained in a relatively taut condition when closed to prevent the entry of air therebeneath both longitudinally and laterally and thereby to prevent particulate leakage, billowing and flapping, and to substantially enhance cover life.
A further object of the present invention resides in the provision of an improved roll-up truck cover assembly of the type mentioned which includes an automatically operable braking apparatus for preventing inadvertent or unintended rotation of the take-up roll when the cover is in the closed position over the opening in the truck body.
A still further object of the invention resides in the provision of a roll-up truck cover assembly of the type mentioned wherein the braking apparatus is of a desirably simple and yet highly effective construction and which may be readily adapted for use at either end of the truck body, installation of course depending upon the front or rear end mounting of the free end of the cover.